Chris Sacca, Silicon Valley Investor (from This American Life)

"Airbnb, multi-billion-dollar business, right? I was one of the first people to see the Airbnb page. And I pulled them aside and said, guys, this is super dangerous. You're renting out a room in somebody's house while they're still there? Somebody's going to get raped or murdered, and the blood is gonna be on your hands. There's no way this'll succeed. That's a $10 billion business today that I'm not an investor in."